diff --git a/src/share/vm/opto/compile.cpp b/src/share/vm/opto/compile.cpp
index f9b3392d0f2e20d08bf96f3c27008bf2377cb04f..1832c63b33e40dd072a22e1a2c101b2b2ff93fa2 100644
--- a/src/share/vm/opto/compile.cpp
+++ b/src/share/vm/opto/compile.cpp
@@ -2192,6 +2192,7 @@ static void final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &fpu ) {
 
   case Op_DecodeN:
     assert(!n->in(1)->is_EncodeP(), "should be optimized out");
+    assert(n->in(0) == NULL, "no control");
     break;
 
   case Op_EncodeP: {
diff --git a/src/share/vm/opto/macro.cpp b/src/share/vm/opto/macro.cpp
index 1152917d9072456d1319f88629dd32b0d4f2500a..4d74a434fec0efacf7b21976e69f9b11bd2d628e 100644
--- a/src/share/vm/opto/macro.cpp
+++ b/src/share/vm/opto/macro.cpp
@@ -1724,6 +1724,13 @@ void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
     if (klass_node == NULL) {
       Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());
       klass_node = transform_later( LoadKlassNode::make(_igvn, mem, k_adr, _igvn.type(k_adr)->is_ptr()) );
+#ifdef _LP64
+      if (UseCompressedOops && klass_node->is_DecodeN()) {
+        assert(klass_node->in(1)->Opcode() == Op_LoadNKlass, "sanity");
+        klass_node->in(1)->init_req(0, ctrl);
+      } else
+#endif
+      klass_node->init_req(0, ctrl);
     }
     Node *proto_node = make_load(ctrl, mem, klass_node, Klass::prototype_header_offset_in_bytes() + sizeof(oopDesc), TypeX_X, TypeX_X->basic_type());